1. Field of the Invention
The present invention relates to a treatment liquid supply apparatus which supplies a treatment liquid to a predetermined object for treatment of a substrate and recovers the supplied treatment liquid for reuse, and to a substrate treatment apparatus including such a treatment liquid supply apparatus. Examples of the substrate to be treated include semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma display devices, substrates for FED (Field Emission Display) devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, and substrates for photo masks.
2. Description of the Related Art
In production processes for semiconductor devices and liquid crystal display devices, substrate treatment apparatuses are typically employed, which are adapted to treat a substrate such as a semiconductor wafer with a treatment liquid. A substrate treatment apparatus of a single substrate treatment type for treating a single substrate at a time, for example, includes a spin chuck which horizontally holds and rotates the substrate, and a treatment liquid nozzle which spouts a treatment liquid toward the substrate held by the spin chuck. A treatment liquid supply pipe extending from a treatment liquid supply apparatus is connected to the treatment liquid nozzle. The treatment liquid is supplied from a treatment liquid tank of the treatment liquid supply apparatus through the treatment liquid supply pipe (see, for example, Japanese Unexamined Patent Publication No. 2006-351709).
In the treatment liquid supply apparatus disclosed in Japanese Unexamined Patent Publication No. 2006-351709, a three-way valve which permits and prohibits the supply of the treatment liquid to the treatment liquid nozzle and a temperature regulator which regulates the temperature of the treatment liquid flowing through the treatment liquid supply pipe are provided in the treatment liquid supply pipe. A return pipe through which the treatment liquid supplied into the treatment liquid supply pipe is fed back to the treatment liquid tank is connected to the three-way valve. The treatment liquid supply pipe, the three-way valve and the return pipe define a circulation passage through which the treatment liquid from the treatment liquid tank is circulated. When the treatment liquid is not supplied to the treatment liquid nozzle, the treatment liquid from the treatment liquid tank is circulated through the circulation passage. Thus, the temperature of the treatment liquid from the treatment liquid tank is regulated by the temperature regulator, so that the liquid temperature in the treatment liquid tank is maintained at a predetermined temperature level.
A treatment liquid recovery pipe extending from the treatment liquid tank is connected to the substrate treatment apparatus. The treatment liquid supplied from the treatment liquid nozzle to the substrate is recovered in the treatment liquid tank through the treatment liquid recovery pipe. The treatment liquid recovered in the treatment liquid tank is supplied again to the treatment liquid nozzle to be supplied to the substrate. Thus, the recovered treatment liquid is reused.
The temperature of the treatment liquid to be recovered in the treatment liquid tank is generally different from that of the treatment liquid to be fed out of the treatment liquid tank toward the treatment liquid nozzle. Therefore, the liquid temperature in the treatment liquid tank is temporarily changed when the treatment liquid is recovered in the treatment liquid tank. However, if the liquid temperature in the treatment liquid tank is changed during the supply of the treatment liquid to the treatment liquid nozzle, the temperature of the treatment liquid to be supplied to the substrate is deviated from an intended temperature level. Therefore, where the treatment to be performed on the substrate is dependent upon the temperature of the treatment liquid, for example, it is impossible to treat the substrate as intended, resulting in a treatment failure.